To make the crust: To the bowl of a stand mixer fitted with a paddle attachment, add cream cheese, butter, sugar and salt until smooth. Add the flour and mix gently until the dough is cohesive.

Turn out dough onto a lightly floured surface and shape the dough into a 1" thick disk, wrap it in plastic, and refrigerate for at least 1 hour.

To make the filling: Whisk together the lime juice, zest, and the sugar. Whisk in the eggs, then the sour cream.

Preheat the oven to 375°F. Grease a 24-cup mini-tart pan.

To assemble: Roll the dough on a floured surface into a circle ⅛" thick. Using a 2¾"biscuit cutter, cut out 24 circles, gathering the scraps and re-rolling the dough as necessary.

Transfer the dough circles to the cups of the pan, pressing into the corners and up the sides of each cup. Pour the filling into each of the tart shells until it nearly reaches the rim of the cup.

Transfer muffin pan to the oven and bake until the crust is golden and the filling is set, 25 to 30 minutes. Allow tarts to cool in pan for about 10 minutes, then carefully remove from the muffin pan and place on a wire rack until cooled completely.